In many present day situations, a person has to adjust various functions and operations of several different electrical and mechanical devices. For example, the driver of a car while driving may have to adjust or control a heating and cooling system, an audio entertainment system, windows, locks, a cruise control system and possibly a navigation system. Conventionally, the user would use buttons, switches, knobs, and other similar mechanical controls to adjust the various functions or operations of these devices. However, with the increased number of controllable devices, along with the increased complexity of each individual device, a person may be required to provide many different inputs through several different buttons, switches, knobs, and other mechanical controls.
To replace the many, separate, and different mechanical controls and to simplify and enhance the control of these many devices, a single aggregate instrument that can relay commands to several devices is often employed, such as a touch panel. By using a touch panel, the user can adjust several different devices by interacting with a hierarchical menu shown through the touch panel from an underlying display to select a particular device and to select a particular function associated with that device.
The touch panel replaces mechanical buttons and switches but typically does not provide the same tactile feedback as a mechanical button or switch. Thus, to enhance the user's interaction with the touch panel, feedback to the user may be provided through visual, auditory, kinesthetic, and/or tactile cues. Kinesthetic feedback, such as active and resistive force feedback, and tactile feedback, such as vibration, texture, and heat, is collectively referred to as “haptic feedback.” Haptic feedback can be used to convey physical force sensations to the user, and generally, the physical forces simulate actuating a mechanical button or switch and provide the user with an indication that the user's input has been accepted.
Conventional haptic feedback can be provided by linear actuators, piezoelectric films, or oscillating mass actuators. Linear actuators provide linear motion using an electromagnetic actuator and simulate a push response. In one conventional system, four individual linear actuators are placed at the four corners of a touch panel. Based on the user's interaction with the touch panel, the four individual actuators will simultaneously impart a slight linear motion to the touch panel so that the user perceives a push response. However, conventional haptic feedback systems using four individual linear actuators are costly to manufacture and difficult to manufacture because such systems require precise alignment of the individual linear actuators to each other for proper movement. Also, linear actuators may not provide an audible feedback that the user's input has been received or accepted.
Haptic feedback is also provided by using piezoelectric films. Piezoelectric films are typically placed over a touch panel and vibrate in response to a touch by the user. Thus, it vibrates or flexes the surface of the touch panel. However, conventional haptic feedback systems using piezoelectric film that vibrate or flex a surface often experience premature failure due to surface stress cracks or subsurface solder joint failures. Also, for certain applications, vibrating the touch panel and its underlying display is not practical.
Furthermore, haptic feedback is also provided by oscillating mass actuators. Oscillating mass actuators shake a component, such as the touch panel and its display, or in some cases, the entire assembly. However, the entire mass of a touch panel assembly cannot be vibrated or pulsed with conventional mounting and assembly systems. Also, similar to systems using piezoelectric films, in certain applications, it may not be practical to vibrate or move the touch panel system and its underlying display.
Lastly, conventional haptic feedback moves the entire touch panel assembly, which can damage the touch panel or its underlying display. In particular, frequent, small movements can damage the fragile electronic components within the touch panel or its underlying display.
Thus, there is a need for a system that provides haptic feedback at reduced cost, simplifies manufacturing of devices with haptic feedback, and reduces premature component failure. Also, there is a need for a system that provides haptic feedback but avoids moving an entire touch panel assembly.